Naming a dinosaur is no easy task. Beneath the apparent mess of prolonged syllables and technical jargon, a vast array of unexpected factors—from politics and religion to wordplay and spelling—can dictate which dino moniker gets officially recognized and which “-saurus” goes extinct. Here are eleven of the all-time greatest showdowns in the storied history of dinosaur nomenclature.

1. “Scrotum humanum,” The World’s First Dinosaur

Behold “Scrotum humanum”, the very first dinosaur name ever coined. In 1763, British naturalist Richard Brookes was shown a femur fragment which he named for the infamous piece of the male genitalia he felt it resembled (I’ll let you figure out which). Scientists never took this seriously and now know the creature as Megalosaurus. In the 1980s, a vocal minority contended that, due to seniority, “Scrotum” should be reinstated. The International Commission on Zoological Nomenclature (ICZN) disagreed and ruled in favor of its more tasteful alternative.

2. T. rex on Trial (Part I)

Thinking he’d found two new dinosaurs, paleontologist H.F. Osborn named them Tyrannosaurus rex and “Dynamosaurus imperiosus” in the same 1905 paper, before realizing that these bone-crunching predators were one and the same. Scientifically, the first name given to an organism in an academic paper takes priority and Osborn happened to have mentioned T. rex on page 262 and “D. imperiosus” on 263—meaning one page of data saved T.rex. BUT WAIT! Stay tuned for another threat to the “tyrant lizard king!”

3. Triceratops vs. Torosaurus

Renowned paleontologist Jack Horner has recently argued that Triceratops and fellow frilled dino Torosaurus were really the same beast. But fear not, Triceratops groupies: the more recognizable name emerged 2 years earlier. Ergo, regardless of the debate’s outcome, everyone’s favorite three-horned herbivore is perfectly safe (if it weren’t already extinct, that is).

4. “Ultrasauros” vs. Procrastination

BYU’s late, great James “Dinosaur Jim” Jensen coined the name Ultrasaurus in 1979. Unfortunately, he didn’t publish his paper on the long-necked dinosaur (“sauropod”) until 1985. By then, Korean paleontologist Haang Mook Kim had independently used Ultrasaurus to designate a completely different animal. D’Oh! Not wanting to lose his awesome name, Jensen replaced the third “u” with an “o” to create “Ultrasauros.” Alas, it later turned out that the “Ultrasauros” material really belonged to a Supersaurus, which had been dubbed earlier by none other than Jensen himself. At least Supersaurus is still pretty cool, unlike the name a certain sauropod got saddled with. More on that later…

5. Arkansaurus vs. “Arkanosaurus” (vs. Bill Clinton)

“Arkanosaurus” and Arkansaurus fridayi were both used as names for Arkansas’ only known dinosaur, until the latter eventually won. Some speculate that Arkansaurus may have been intended as a state-based pun. While this is uncertain, at least a few political punsters definitely did latch onto the dinosaur: former governor Bill Clinton was nicknamed “Arkansaurus taxandspendus” by American conservatives in his 1996 presidential run.

6. Iguanodon vs. the World

Before the word “dinosaur” was even invented, the wife of Sussex doctor Gideon Mantell stumbled upon a fossilized tooth in 1825 and the scientific community laughed at his imaginative assertion that it had belonged to an enormous, plant-eating reptile. Since huge, scaly herbivores don’t exist in his day, referring to the tooth’s owner as Iguanodon—or “iguana tooth”—seemed ludicrously inappropriate when an ancient rhinoceros looked like its most likely source. But as more complete fossils confirming Mantell's hypothesis began to turn up en masse, the magnificent reality of these creatures was celebrated the world over, and Iguanodon turned into a household name.

7. T. rex on Trial (Part II)

For two incomplete vertebrae, famed paleontologist Edward Drinker Cope invented the clunky moniker Manospondylus gigas in 1892. In 2000, it was confirmed that his specimens were identical to T. rex backbones, and some worried that the world’s most famous dinosaur would have to be rechristened. However, a new ICZN rule enacted that year included a loop-hole allowing secondary names to take priority if the original wasn’t deemed valid after 1899. Since M. gigas was never widely used after the cutoff date, the “tyrant lizard king” was saved.

8. Archaeopteryx vs. “Griphosaurus”

Named by in 1861 by Christian Erich Hermann von Meyer and meaning “ancient wing,” Archaeopteryx lithographica has long been recognized as a “missing link” between modern birds and their dinosaurian ancestors. Von Meyer's rival, Johann Andreas Wagner, denied that this was a transitional fossil and proposed calling it “Griphosaurus problematicus” (“the problematic griffin lizard”) later that year. “Darwin and his adherents,” he wrote, “will probably employ the new discovery as … justification of their strange views upon the transformation of animals. But in this they will be wrong.” His pointed words fell on deaf ears, and Meyer’s name (like Darwin’s theory) won out.

9. The “Big Dead Lizard”

The name Syntarsus was accidentally given to two creatures: a predator, discovered by paleontologist Mike Raath in 1969, that lived approximately 180 million years ago; and a modern beetle that had been found a century earlier. So insect expert Michael Ivie formally re-named Raath’s dino Megapnosaurus, which literally means “big, dead lizard” as a joking dig at dinosaur science. Paleontologists weren’t laughing. Livid that his life’s work underwent a name change without his input, Raath wrote, “I am myself very disappointed that the normal dictates of professional courtesy, let alone professional ethics, have apparently been disregarded.” To many colleagues, the fact that this dinosaur now went by a deliberately silly title was salt thrown on an open wound. Ivie’s actions remain a touchy subject worldwide.

10. Presumptuous Protoavis

Protoavis really ruffles some feathers. When Sankar Chaterjee called a partial skeleton he’d found Protoavis texensis in 1991, he believed that it was a primitive bird, thus pushing the date of avian origins back by roughly 60 million years. His bold claim has since been almost universally rejected, making a name that literally means “first bird” one of the most controversial in modern science (in fact, Protoavis might not have even existed at all, for its bones appear to belong to several different animals).

11. “Brontosaurus” Thunders Off

As many of us know, the celebrated “Brontosaurus” never existed. In 1879, legendary fossil hunter Othneil Charles Marsh discovered a nearly-perfect sauropod skeleton. Calling it “Brontosaurus” (“thunder lizard”), he put it on display with the head of a Brachiosaurus that had been found nearby at a different site (since nobody likes a decapitated dino). “Brontosaurus” sank into limbo in 1903, when paleontologists found that it was identical to Apatosaurus (“deceptive lizard”), a sauropod named in 1877. Yet, bronto-lovers can take heart in maverick paleontologist Robert Bakker, who’s argued that the original “Brontosaurus” skeleton is unique enough to merit its own genus, meaning its name would be at long last restored. Most scientists dismiss these claims, so the odds are slim. But maybe one day, “Brontosaurus” will stomp into our museums once more, just as it roams through our imaginations.